Our generation is experiencing a lot of light pollution. This can come from neon signs flashing in our shopping areas, to LED bulbs in our homes and offices. In the past decade, since information technology took over, we also seem to be glued to our screens. This background light emitted by these screens is known as blue light since it comes from that range of the light spectrum.
What is blue light?
Blue light is one of the colours from the light spectrum and contains a wave length of 415-455 nm. The major source of blue light is from sunlight, which during the day keeps our mood upbeat and our mind sharp and active. Earlier, our ancestors were up at the crack of dawn and went to sleep shortly after sundown. This coincided with the rising and setting of the sun. Most of their work was done during the day (where the blue light wavelength was at its peak).
However, nowadays our blue light exposure goes way beyond the normal sunrise and sunset cycle and extends to late at night. Many of us may be working night shifts where this light is emitted from computer screens and phones. People prefer to unwind during the evening/night in front of the TV or with their phones checking mails, browsing or going through social media.
What this light means for our sleep
Our bodies go through natural sleep and wake cycle. During the time we sleep, the organs and cells heal, build and restore. Our organs help in detoxifying and we get some much- needed rest. On an average, a person needs between 6 to 8 hours of sleep each night. This is in sync with our circadian rhythm. Being exposed to blue light during the night upsets this rhythm and makes it harder to fall asleep. Switching off your electronic devices 1-2 hours before bedtime and sleeping in a dark room can help give you better quality and restful sleep.
The dark side of blue light
With the need for energy efficient sources, LED lighting was chosen for optimal lighting. They gave out bright white light and were energy efficient. This found its way into our compact devices like mobile phones, tablets and e-readers for backlit liquid crystal displays. This has also changed the face of traditional reading. Earlier, light was used to reflect off our books so we could read. But now, our reading devices themselves are being directly illuminated from within!
Since prolonged exposure to blue light is a relatively new phenomenon, not many long-term studies have been done to study its effects on our health. However, certain studies have shown a link between upset circadian rhythms and its negative effects on digestive health, sleep impairment and certain cancers. Excessive exposure to blue light is known to affect human chronobiology (Chronobiology is the study of living organisms, their internal biological clocks and the way they adapt to solar and lunar rhythms) negatively.
When light hurts
In addition, prolonged exposure to light has other harmful effects. These occur when the light causes damage to the retina and can occur in 3 ways- photomechanical, photochemical and photothermal. These cause damage to the retina and its associated photoreceptors. Cumulative exposure to blue light can cause eye strain leading to retinal damage. Children’s eyes in particular are affected by this blue light exposure.
Exposure to blue light could result in lack of sleep/ difficulty in falling asleep. This in turn, lowers quality of the rest we get each night. Upsetting our sleep hormones also affects other hormonal processes (leptin- gives a feeling of fullness) related to the way we metabolize and use energy, which in turn, can make it harder to regulate our appetites and lose weight.
Safety Tips:
Switch off all electronic devices 2-3 hours before bedtime.
Opt for reading mode on your devices (this gives a yellowish colour to your page, which places less strain on the eyes).
Practise the 20-20-20 rule- every 20 minutes, look 20 meters away and blink for 20 seconds.
Get sufficient sleep, on an average between 6 to 8 hours.
Go back to good old-fashioned reading from a paper-based book.
Wear anti-reflective glasses or consider installing an anti-glare screen on your electronic devices.
Get sunlight exposure during the day, this helps boost your mood and alertness (you also get vitamin D), which in turn helps you sleep better at night.
Dim the lights around the house, especially at night.
References
Blue Light – Is there risk of harm?. (2019). https://opto.ca/health-library/blue-light-is-there-risk-of-harm
Fleming, A. (2019). The truth about blue light: does it really cause insomnia and increased risk of cancer?. https://www.theguardian.com/lifeandstyle/2018/may/28/blue-light-led-screens-cancer-insomnia-health-issues
How Blue Light Is Ruining Sleep & Making Us Fat. (2019). https://www.alexfergus.com/blog/how-technology-blue-light-is-ruining-sleep-making-you-sick-fat-tired-and-how-to-fix-it
Publishing, H. (2019). Blue light has a dark side - Harvard Health. https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side
Reduce your exposure to blue light at night. (2019). https://green.harvard.edu/tools-resources/green-tip/reduce-your-exposure-blue-light-night
Rettner, R. (2019). Keeping Your TV on at Night May Lead to Weight Gain. https://www.livescience.com/65681-light-night-weight-gain.html
Schmerler, J. (2019). Q&A: Why Is Blue Light before Bedtime Bad for Sleep?. https://www.scientificamerican.com/article/q-a-why-is-blue-light-before-bedtime-bad-for-sleep/
The Dark Side of Blue Light - Two Sides. (2019). https://www.twosides.info/UK/the-dark-side-of-blue-light/
What is Blue Light?. (2019). https://blutechlenses.com/blog/what-is-blue-light/
Zhao, Z. C., Zhou, Y., Tan, G., & Li, J. (2018). Research progress about the effect and prevention of blue light on eyes. International journal of ophthalmology, 11(12), 1999–2003. doi:10.18240/ijo.2018.12.20
Hatori, M., Gronfier, C., Van Gelder, R. N., Bernstein, P. S., Carreras, J., Panda, S., … Tsubota, K. (2017). Global rise of potential health hazards caused by blue light-induced circadian disruption in modern aging societies. NPJ aging and mechanisms of disease, 3, 9. doi:10.1038/s41514-017-0010-2
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